Milk flow detecting method and device monitors a flow of milk in a milk line which is connected to a teat cup and which has an aeration opening, like in a milking device. For this purpose, the milk filling level is monitored in a measuring section of the line. If the variation therein is too little, the absence of a flow, or at least an inadequate flow, is established. If, additionally, a (sufficient) filling level is detected, it can be concluded that there is an obstructed aeration opening.
